Additive composition for both rinse water recycling in water recycling systems and simultaneous surface treatment of lithographic printing plates

ABSTRACT

Additive compositions suitable for rinse water used for processing lithographic printing plates, particularly to additive compositions for rinse water in water recycling systems, are disclosed. The additive compositions contain at least one water-soluble film-forming polymer; optionally, at least one pH regulating agent capable of maintaining the pH value of an aqueous solution at about 7 or below; and at least one compound selected from the group consisting of phosphonic acid derivatives of formula I.  
                 
 
     in which X is C 2 -C 6  alkylene or  
                 
 
     in which: k is 0 or 1; m is 1, 2, or 3; p is 1, 2, or 3; r is an integer from 10 to 20; R 1  and R 3  are each independently H or C 1 -C 4  alkyl; R 2  and R 4  are each independently H, OH or C 1 -C 4  alkoxy; and Y is —R 6 N—(CH 2 ) n —(NR 5 ) q —, in which q is 0 or 1, n is an integer from 0 to 8, and R 5  and R 6  are each independently H, C 1 -C 4  alkyl, or —CH 2 —P(O)(OH) 2 .

FIELD OF THE INVENTION

[0001] The invention relates to additive compositions suitable for rinsewater used for processing lithographic printing plates, particularly toadditive compositions for rinse water in water recycling systems.Further, the invention refers to aqueous concentrates of said additivecompositions, to a method of processing an imagewise exposedlithographic printing plate by using rinse water containing saidadditive composition, and to printing plates obtained by said method.

BACKGROUND OF THE INVENTION

[0002] The art of lithographic printing is based upon the immiscibilityof oil and water, in which oily material or ink is preferentiallyretained by the image areas and the water or fountain solution ispreferentially retained by the non-image areas of the printing plate.When a suitably prepared surface is moistened with water and ink isapplied, the background or non-image areas retain the water and repelthe ink while the image areas accept the ink and repel the water. Theink on the image areas is then transferred to the surface of a materialupon which the image is to be reproduced, such as paper, cloth andplastics. Commonly, the ink is transferred to an intermediate materialcalled the blanket, which in turn transfers the ink to the surface ofthe material upon which the image is to be reproduced.

[0003] Lithographic printing plates can be either negative-working orpositive-working, and comprise one or more radiation-sensitive layers ona suitable substrate, such as metal or polymeric support. Theradiation-sensitive layer generally includes one or moreradiation-sensitive components that may be dispersed in a suitablebinder. Alternatively, the radiation-sensitive component can also be thebinder material. Certain useful printing plates can be used either aspositive-working or negative-working.

[0004] A negative-working printing plate generally has a light sensitivelayer composed of a radiation-sensitive component such as an unsaturatedresin on a suitable substrate. Upon imagewise exposure to light, theexposed areas are hardened, leaving non-exposed areas removable duringdevelopment. Certain negative-working printing plates contain novolacresins, a cross-linking agent, and a radiation-sensitive component thatproduces acid on exposure. By subsequently heating the plate, only theexposed areas are cured and the unexposed areas can be removed by adeveloper. The exposed, hardened areas are therefore oleophilic and willaccept ink while the non-exposed underlying areas of the substrate arehydrophilic.

[0005] An alkaline developable positive-working printing plate generallyhas a light sensitive layer comprising a novolac resin and aradiation-sensitive component such as an o-diazoquinone ordiazonaphthoquinone compound. Upon imagewise exposure to imagingradiation, the radiation-sensitive component is converted to thecorresponding carboxylic acid. The use of an alkaline developer willremove only the exposed areas of the radiation-sensitive layer, leavingthe surface of the support. Because the surface of the support ishydrophilic, the uncovered non-image area attracts water and repels theoily ink. The image area remaining after development is oleophilicthereby repelling water and attracting the printing ink.

[0006] After subjecting the imagewise exposed printing plate to asuitable developer solution the plate is rinsed with water (“rinsewater”) in order to remove the developer solution adhering thereto.Subsequently, the plate is usually subjected to a gumming step in orderto protect the plate against air and pollution during storage beforebeing used for printing.

[0007] The rinsing of the plate with fresh water results in a highconsumption of water. In addition to the high costs for the fresh water,there is an additional high cost for waste-water treatment, because alarge amount of waste water contaminated with both the organicsubstances of the radiation-sensitive layer and the ingredients of theused developer has to be treated. Therefore, there is a tendency to usea water recycling system in order to save water and costs. This meansthat the printing plates are no longer rinsed with fresh water (like tapwater and well water) but with water that is permanently in circulation.However, due to the permanent recycling the water quality decreases bythe uptake of developer solution and coating components during therinsing step; consequently the rinsing efficiency decreases and theimage and non-image areas of the plate might be interfered.

[0008] Furthermore, it is time consuming to carry out the rinsing andgumming subsequently in separate process steps. Therefore, it would bedesirable to overcome the necessity of a separate gumming step.

[0009] Therefore, a need exists for a method of processing an imagewiseexposed printing plate in which the rinse water can be recirculatedwithout a decrease of rinsing efficiency, which does not require of aseparate gumming step, and which can be carried out by the use ofconventional processors, i.e. which does not require new and/oradditional equipment.

SUMMARY OF THE INVENTION

[0010] The invention is an additive composition that can be added to therinse water used to rinse an imagewise exposed and developedlithographic printing plate (also known as a printing plate precursor),an aqueous concentrate comprising the additive composition, a rinsewater, a method of for processing an imagewise exposed lithographicprinting plate using the rinse water, and an exposed and developedlithographic printing plate (also called a printing form) produced bythe method of the invention. The additive composition comprises:

[0011] (a) at least one water-soluble film-forming polymer; and

[0012] (b) at least one compound selected from the group consisting ofphosphonic acid derivatives of formula I

[0013] in which X is C₂-C₆ alkylene or

[0014] in which: k is 0 or 1; m is 1, 2, or 3; p is 1, 2, or 3; r is aninteger from 10 to 20; R¹ and R³ are each independently H or C₁-C₄alkyl; R² and R⁴ are each independently H, OH or C₁-C₄ alkoxy; and Y is—R⁶N—(CH₂)_(n)—(NR⁵)_(q)—, in which q is 0 or 1, n is an integer from 0to 8, and R⁵ and R⁶ are each independently H, C₁-C₄ alkyl, or—CH₂—P(O)(OH)₂. Preferably, the additive composition further comprisesat least one pH regulating agent capable of maintaining the pH value ofan aqueous solution at about 7 or below.

DETAILED DESCRIPTION OF THE INVENTION

[0015] One essential component of the additive composition is at leastone film-forming water-soluble polymer. Typical examples of suchpolymers include natural substances and modified products thereof likegum arabic, starch derivatives, for instance, dextrin, wasted dextrine,enzyme-modified dextrin, etherified enzyme-modified dextrin,carboxymethylated starch and starch phosphate, octenyl succinatedstarch, alginates or cellulose derivatives, for instance, carboxymethylcellulose, carboxyethyl cellulose, hydroxyethyl cellulose, methylcellulose and hydroxypropyl methyl cellulose; and synthetic substanceslike polyvinyl alcohol and derivatives thereof, polyvinyl pyrrolidone,polyacrylamide and copolymers thereof, polyacrylic acid and copolymersthereof, styrene/maleic anhydride copolymers, vinyl methyl ether/maleicanhydride copolymer and vinyl acetate/maleic anhydride copolymers. Thesewater-soluble polymers may be used alone or in combination and theamount thereof in the additive composition of the invention preferablyranges from about 0.1 to 80% by weight, more preferably about 5 to 30%by weight on the basis of the total amount of additives.

[0016] Another essential component of the additive composition is atleast one component selected from the group consisting of phosphonicacid derivatives of formula I

[0017] in which X is C₂-C₆ alkylene or

[0018] in which: k is 0 or 1; m is 1, 2, or 3; p is 1, 2, or 3; r is aninteger from 10 to 20; R¹ and R³ are each independently H or C₁-C₄alkyl; R² and R⁴ are each independently H, OH or C₁-C₄ alkoxy; and Y is—R⁶N—(CH₂)_(n)—(NR⁵)_(q)—, in which q is 0 or 1, n is an integer from 0to 8, and R⁵ and R⁶ are each independently H, C₁-C₄ alkyl, or—CH₂—P(O)(OH)₂.

[0019] As used herein the terms “alkyl”, “alkylene” and “alkoxy” includeboth straight-chain and branched-chain groups.

[0020] Preferred additive compositions compriseshydroxyethanediphosphonic acid or suitable salts thereof,hexamethylenediamino-tetra(methylenephosphonic acid) or suitable saltsthereof, aminotri(methyl-enephosphonic acid) or suitable salts thereof,as phosphonic acid derivative of formula 1. Sodium salts thereof areespecially preferred. Besides single compounds, mixtures of two or morethereof can be used.

[0021] The amount of the at least one phosphonic acid derivative is notlimited, but in preferred embodiments the amount is from about 0.1 to 30wt %, especially preferred is from about 3 to 20 wt %, based on thetotal amount of additives.

[0022] The additive composition of the invention preferably contains apH regulating agent, or buffer, capable of maintaining the pH of anaqueous solution at about pH 7 or below (preferably in the range ofabout pH 5 to pH 6), i.e. capable of compensating hydroxide ions fromthe alkali developer. Suitable pH regulating agents comprise, forexample, citric acid, citrates (citric acid salts, preferably alkalimetal salts of citric acid), boric acid, acetic acid, propionic acid,succinic acid, phosphates, phosphoric acid andaminotris-(methylene-phosphonic acid). They are preferably used in aconcentration of about 0.01 to 1 mol per 100 g additive composition,more preferably about 0.01 to 0.5 mol. The pH regulating agent should becapable of keeping the pH of an aqueous composition at about 7 or belowas long as possible when hydroxide ions are added.

[0023] The term “water” as used herein includes tap water, well water,demineralized (deionized) water and recirculated rinse water, unlessdefined otherwise.

[0024] The additive composition of the invention optionally comprises atleast one further additive selected from the group consisting ofantifoaming agents, biocides, corrosion inhibitors, chelating agents andsurfactants.

[0025] Suitable antifoaming agents are for instance Silicone Antifoamemulsion SE57 (Wacker), TRITON® CF32 (Rohm & Haas), AKYPO® LF2 (ethercarbonic acid, Chem Y), Agitan 190 (Müinzing Chemie), TEGO® Foamese 825(modified polysiloxane, TEGO Chemie Service GmbH, DE). Silicone-basedantifoaming agents are preferred. They can be eitheremulsion-dispersible or soluble in water. Preferably, the amount ofsilicon-based antifoaming agents is about 0.005 to 5 wt % based on thetotal amount of additives; more preferably about 0.005 to 1 wt %. Theamount of other antifoaming agents is preferably about 0.1 to 5 wt %,more preferably about 0.5 to 3 wt % based on the total amount ofadditives. It is possible to use a single antifoaming agent or acombination of two or more thereof.

[0026] The biocide should be effective against bacteria, fungi and/oryeasts. Suitable biocides are N-methylol-chloroacetamide, benzoic acid,phenol or its derivatives, formalin, imidazole derivatives, sodiumdehydro-acetate, isothiazolinone derivatives, benzotriazole derivatives,amidines, guanidine derivatives, quaternary ammonium salts, pyridine,quinoline derivatives, diazine, triazole derivatives, oxazoles andoxazine derivatives, and mixtures thereof. Although their amount variesdepending on the kind of bacteria, fungi and/or yeasts, it is preferablyabout 1 to 80 wt % based on the total amount of additives, morepreferably about 30 to 80 wt %. It is possible to use a single biocideor a mixture of two or more.

[0027] Suitable examples of corrosion inhibitors are magnesium nitrate,zinc nitrate, calcium nitrate, sodium nitrate, potassium nitrate,lithium nitrate, ammonium nitrate and mixtures thereof. Typically theyare used in an amount of about 0.5 to 10 wt % based on the total amountof additives, more preferably about 1 to 5 wt %. The inhibitors can beused individually or as a mixture of two or more thereof.

[0028] Examples of suitable chelating agents include aminopolycarboxylicacid and salts thereof such as ethylenediamine-tetraacetic acid andpotassium or sodium salt thereof, diethylenetriamine-pentaacetic acidand potassium or sodium salt thereof, triethylenetetramine-hexaaceticacid and potassium or sodium salt thereof, hydroxyethylethylenediamine-triacetic acid and potassium or sodium salt thereof,nitrilotriacetic acid and potassium or sodium salt thereof,1,2-diaminocyclohexane-tetraacetic acid and potassium or sodium saltthereof and 1,3-diamino-2-propanol tetraacetic acid and potassium orsodium salt thereof; and an organophosphonic acid, phosphonoalkanetricarboxylic acid or salts thereof such as2-phosphonobutanetricarboxylic acid-1,2,4 and potassium or sodium saltthereof, 2-phosphonobutane-tricarboxylic acid-2,3,4 and potassium orsodium salt thereof, 1-phosphonoethane-tricarboxylic acid-2,2,2 andpotassium or sodium salt thereof, aminotris-(methylene-phosphonic acid)and potassium or sodium salt thereof and sodium gluconate; the chelatingagents can be used singly or in combination of two or more thereof.Organic amine salts of the foregoing chelating agents may be usedeffectively instead of potassium and sodium salts thereof. Thesechelating agents are preferably used in an amount ranging from about 0.1to 30% by weight, more preferably about 3 to 10% by weight on the basisof the total amount of additives. Since the phosphonic acid derivativesof formula I are able to form a complex with for instance magnesium andcalcium ions it is not necessary to use one of the chelating agentsabove. However, depending on for instance the hardness of the rinsewater to which the additive composition is added, it might beadvantageous to use a chelating agent in addition to the phosphonic acidderivatives of formula I.

[0029] Suitable surfactants include anionic surfactants like fatty acidsalts, abietic acid salts, hydroxyalkanesulfonic acid salts, dialkylsulfosuccinate salts, alkyl naphthalenesulfonate salts, alkyl-phenoxypolyoxyethylenepropylsulfonate salts, polyoxyethylene alkylsulfophenylether salts, sodium salt of N-methyl-N-oleyltaurine, disodium salt ofN-alkylsulfosuccinic acid amide, petroleum sulfonic acid salts, sulfatedcastor oil, sulfated tallow, sulfuric acid ester salts of fatty acidalkyl esters, alkylsulfate ester salts, polyoxyethylene alkyl ethersulfuric acid ester salts, fatty acid monoglyceride sulfuric acid estersalts, polyoxyethylene alkylphenyl ether sulfuric acid ester salts,polyoxyethylene styrylphenyl ether sulfuric acid ester salts,alkylphosphate ester salts, polyoxyethylene alkyl ether phosphoric acidester salts, polyoxyethylene alkylphenyl ether phosphoric acid estersalts, partially saponified styrene-maleic anhydride copolymers,partially saponified olefin-maleic anhydride copolymers and condensatesof naphthalene sulfonic acid salt and formalin; alkylbenzene sulfonates,alkane sulfonates, alkylsulfates and alkylethersulfates, nonionicsurfactants like glycerin, ethylene glycol, triethylene glycol, sorbitanfatty acid ester, alkyl phenolethoxylates, fatty alcohol ethoxylates,alkyl polyglucosides and N-methylglucamides; and cationic surfactantslike quaternary ammonium compounds with one or two hydrophobic groupsand salts of long chain primary amines.

[0030] The surfactants are preferably used in an amount of about 0.5 to50 wt % based on the total amount of additives, more preferably about 5to 20 wt %. Besides the use of a single surfactant, it is also possibleto use a combination of two or more thereof.

[0031] Depending on the particular components used for the additivecomposition and their amounts the composition can for instance beformulated as powder, tablet, paste, emulsion, suspension or solution.

[0032] Furthermore, the additive composition can be incorporated intowater in order to obtain an aqueous concentrate thereof. Preferably theamount of additive composition incorporated is about 40 to 90 wt % basedon the amount of water used, more preferably about 50 to 80 wt %.

[0033] The invention also relates to a method for processing animagewise exposed lithographic printing plate. Said method comprises

[0034] (i) applying a developer to the exposed plate and

[0035] (ii) rinsing the plate thereafter with water (so called rinsewater) which contains the additive composition according to theinvention

[0036] The method can be used for processing any positive or negativeworking lithographic printing plate that is developed by means of adeveloper solution.

[0037] The developer can be any developer useful for removing thenon-image areas of an imagewise exposed plate.

[0038] The developer can be any developer useful for removing thenon-image areas of an imagewise exposed plate. Depending on the kind ofplate (i.e. the ingredients of the radiation-sensitive composition) aperson skilled in the art is able to select a suitable developer for theimagewise exposed plate. Alkaline developers are disclosed, for example,in Yamasue, U.S. Pat. No. 4,259,434; Miller, U.S. Pat. No. 5,851,735;Hall, U.S. Pat. No. 5,122,243; West, U.S. Pat. No. 5,368,974; andFiebag, U.S. Pat. No. 6,143,479.

[0039] The amount of additive composition and aqueous concentrate,respectively added to the rinse water depends on the m² plates to berinsed and the type of plate. The amounts of components given below aresuitable for most applications.

[0040] It is preferred that the rinse water used in the method accordingto the invention comprises about 0.0004 to 8 wt % based on the rinsewater of the at least one film-forming polymer, more preferably about0.02 to 4 wt %, most preferably about 0.25 to 1.5 wt %.

[0041] Concerning the pH regulating agent, it is preferred to use about1 to 100 mmole/L of rinse water, more preferably about 1 to 50 mmole/L.The pH of the recirculated rinse water should be kept at about 7 orbelow as long as possible. The rinse water can, however, still be usedfor processing when the pH is above 7 as long as the pH is not higherthan about 9.5.

[0042] At least one phosphonic acid derivative is preferably present inan amount of about 0.0004 to 3 wt % based on the rinse water, morepreferably about 0.01 to 2 wt %, most preferably about 0.15 to 0.8 wt %.

[0043] The rinse water can optionally contain about 0 to 0.5 wt %, basedon the amount of rinse water, of antifoaming agent, more preferably theamount is about 0.00002 to 0,1 wt % for silicone-based agents and about0.0002 to 0.3 wt % for other antifoaming agents.

[0044] For inhibiting the growth of bacteria, fungi, yeast and algae itis preferred to use about 0 to 8 wt %, based on the amount of rinsewater, of at least one biocide, more preferably about 0.12 to 8 wt %,most preferably about 1.5 to 5 wt %.

[0045] At least one corrosion inhibitor is preferably present in anamount of about 0 to 2 wt %, based on the amount of rinse water, morepreferably about 0.004 to 0.5 wt %, most preferably about 0.1 to 0.5 wt%.

[0046] Concerning the chelating agent, it is preferred to use about 0 to3 wt % based on the rinse water, more preferably about 0.01 to 1 wt %,most preferably about 0.05 to 0.5 wt %.

[0047] It is preferred that the rinse water contains about 0 to 5 wt %,based on the amount of rinse water, of at least one surfactant, morepreferably about 0.02 to 2 wt %, most preferably about 0.05 to 0.5 wt %.

[0048] The rinse water containing the additives can be prepared byadding a suitable amount of the additive composition according to theinvention to the rinse water or by adding a suitable amount of theadditive concentrate according to the invention. The water used can beselected from the group consisting of tap water, well water,demineralized water and recirculated rinse water.

[0049] A person skilled in the art is able to select a suitable amountof the additive composition and additive concentrate, respectively andhe/she is also able to select a suitable additive compositionconcentrate depending on the processor used, the type of water, type ofdeveloper and type of radiation-sensitive layer on the printing plate.

[0050] According to a preferred embodiment the rinse water isrecirculated with a conventional water recycling system. By the use ofthe additive composition of the invention it is possible to re-use therinse water several times without any decrease in the rinsing efficiencyand/or any negative effect on the printing plate qualities. The amountof m² of plate which can be rinsed depends on the kind of developerused, the kind of plate to be rinsed and the additive composition. Therinse water can be recirculated and re-used until its pH value is about9.5. A higher pH value deteriorates the plate and is therefore notsuitable; by the buffering agent present in the additive composition ofthe invention the time until the pH of the rinse water reaches pH 9.5 isprolonged.

[0051] The plate obtained by the method according to the invention neednot to be subjected to a subsequent gumming step. However, it is withinthe scope of the present application that the obtained plate issubjected to a subsequent gumming step.

[0052] The use of the additive composition and additive concentrate,respectively, provides the following advantages:

[0053] The additive composition in the rinse water leads to anabsolutely clean development of plates, that means that all problemscaused by developer drag-in (carry over) are inhibited. Plates areoptimally prepared for press without the need for a further gumming step(hydrophilic properties, corrosion protection, pH-value).

[0054] If the circulation water is used to rinse off image remover (forexample, a Sprinter 72iK water recycling system from Kodak PolychromeGraphics) all corrected image areas become hydrophilic again.

[0055] Scratches on the plate's surface become hydrophilic again.

[0056] The problem of algae and bacteria growth upon the effect of lightor temperature or caused by prolonged bath life of the rinse water isprevented.

[0057] There are no deposits of calcium and magnesium salts, which maycause major problems on press (like blinding and toning).

[0058] Dragged-out alkaline developer components are neutralized so thatthere is no decrease in rinsing efficiency.

[0059] The anti-corrosive properties of the phosphonates and phosphateslead to a resealing of the plate surface upon rinsing, which is anoptimum preparation for printing. The results are very good hydrophilicproperties, excellent water-ink balance, fast roll-up on press and notoning.

[0060] The plate surface is additionally sealed and protected againstfingerprints, etc. by the water-soluble film-forming resin. Dirtparticles that may have been dragged-in are bound and cannot penetrateinto the plate surface. Any conventionally used processing equipment canbe used for carrying out the method of the invention.

[0061] The following examples serve to provide a more detailedexplanation of the invention without limiting it.

EXAMPLES

[0062] Additive Compositions

[0063] Two additive compositions according to the invention as well asone comparative composition were prepared by mixing the components inthe desired amounts. The components of each composition as well as theamounts of all components are shown in Table 1. TABLE 1 CompoundComposition 1 wt % Composition 2 wt % Composition 3 wt % DEQUEST ® 2000¹⁾ 4.20 4.02 — DEQUEST ® 2006 ²⁾ 8.86 8.46 10 MERGAL ® K6N ³⁾ 75.07  —70.44  Parmetol B70 ⁵⁾ — — 0.40 PROXEL ® GXL ⁶⁾ — 71.73  1.61PREVENTOL ® ON extra ⁷⁾ — — 0.24 boric acid — 0.72 0.80 TRITON ® GR5 ⁸⁾0.30 — DOWFAX ® 8390 ⁹⁾ — 0.72 0.40 dextrine — 14.34  16.09  hydroxyethyl cellulose 11.55  — silicone antifoaming agent 0.02 0.01 0.02 Total100 100 100

[0064] 1) aminotris-(methylene-phosphonic acid) available from Brenntag,Germany

[0065] 2) aminotris-(methylene-phosphonic acid), sodium salt availablefrom Brenntag, Germany

[0066] 3) N-methylole-chloroacetamide available from Honeywell, USA

[0067] 4) combination of bactericide and fungicide available fromSchülke & Mayr GmbH, Germany

[0068] 5) 1,2-benzisothiazoline-3-on available from Zeneca Biocides,Manchester, UK

[0069] 6) sodium-2-phenyl-phenolate available from Bayer, Germany

[0070] 7) dioctyl sodium sulfosuccinate available from Union Carbide

[0071] 8) sodium n-hexadecyl diphenyloxide disulfonate available fromDow

[0072] Aqueous Concentrates

[0073] Aqueous concentrates of the invention were prepared by mixingeach of compositions 1 to 3 with water (200 hardness). Additionally, amixture of water and MERGAL® K9N was prepared for comparative reasons(concentrate 4). Details of the concentrates are summarized in Table 2.TABLE 2 Concentrate 4 Concentrate 1 Concentrate 2 Concentrate 3(Comparative) Component wt % wt % wt % wt % Composition 1 66.6 — — —Composition 2 — 69.71 — — MERGAL ® K9N* — — — 50 Composition 3 — — 62.16— Water 33.4 30.29 37.84 50 (demineralized)) Total 100 100 100 100

[0074] Rinsing with standard water recycling unit

[0075] a) Negative working lithographic printing plates

[0076] Kodak Polychrome Graphics WINNER® plates were developed in aprocessor, type Sprinter 72 N of Kodak Polychrome Graphics, equippedwith a standard water recycling system.

[0077] Processing speed: 80 cm/min.

[0078] The processor was filled with 30 liters of Kodak PolychromeGraphics Negative Developer 956 and 60 liters circulation water.

[0079] 5% (based on the amount of circulation water; 3000 mL) ofconcentrates 1 to 4 and water with 20° hardness, respectively, wereadded to the circulation water.

[0080] 5 m² printing plates were developed per liter rinse water.

[0081] b) Positive working lithographic printing plates

[0082] Kodak Polychrome Graphics Virage™ plates were developed in aprocessor, type Sprinter 72 N of Kodak Polychrome Graphics, equippedwith a standard water recycling system.

[0083] The processor was filled with 30 liters of Kodak PolychromeGraphics Positive Developer 4030 and 60 liters circulation water.

[0084] The developer strength was kept constant by means of top up withdeveloper 4030.

[0085] Processing speed: 100 cm/min.

[0086] 5% (3000 mL) of concentrates 1 to 4 comparative concentrates andwater with 20° hardness, respectively, were added to the circulationwater.

[0087] 5 m² printing plates were developed per liter rinse water.

[0088] c) Digital newspaper plates

[0089] Kodak Polychrome Graphics Thermal News plates were developed in aprocessor, type Sprinter 72 N of Kodak Polychrome Graphics, equippedwith a standard water recycling system.

[0090] The processor was filled with 30 liters of Kodak PolychromeGraphics Developer 980 and 60 liters circulation water.

[0091] Processing speed: 80 cm/min.

[0092] 5% (3000 mL) of concentrates 1 to 4 and water with 200 hardness,respectively, were added to the circulation water.

[0093] 5 m² printing plates were developed per liter rinse water.

[0094] In the Kodak Polychrome Graphics processor Sprinter 72 N thedeveloped printing plates a, b and c were thoroughly squeezed by rubberrollers and then rinsed by circulation water.

[0095] Per m² plate about 10 to 12 L rinse water were used.

[0096] After rinsing with circulation water, plates were squeezed againby rubber rollers, dried with infrared and stored for 24 hours and puton press.

[0097] Printing test with the developed plates

[0098] The printing plates obtained after the rinsing described abovewere mounted on a press and used for printing. The results are shown inTable 3. TABLE 3 ADDITIVE WINNER ® Virage ™ Thermal News ™ (5 wt %addition) developed with 956 developed with 4030 developed with 980Concentrate 1 Ok Ok Ok Concentrate 2 Ok Ok Ok Concentrate 3 Ok Ok OkConcentrate 4 toning toning toning (comparison) Water with 20° toningtoning toning hardness (comparison)

[0099] As apparent from the above table, no printing problems arise whenrecirculated rinse water that contains an additive composition accordingto the invention is used. Contrary thereto toning occurs during printingwhen the recirculated water does not contain any additive or contains anadditive composition that is not according to the invention.

[0100] Rinsing with Water Recycling System iK and Print test with thedeveloped plates

[0101] Kodak Polychrome Graphics Virage™ plates were developed in aprocessor, type Sprinter 72 iK of Kodak Polychrome Graphics which isequipped with a water recycling system.

[0102] The processor was filled with 30 liters of Kodak PolychromeGraphics Positive Developer 4030 and 60 liters circulation water.

[0103] The developer strength was kept constant by means of top up withdeveloper 4030.

[0104] Processing speed: 100 cm/min.

[0105] The developed and dried printing plates were corrected with theKodak Polychrome Graphics Image Remover 243.

[0106] Plates were run through the second in-feed of the Sprinter 72Nand the image remover was rinsed off by the water recycling system iK.Residues of the image remover that had been dragged in were filtered bya filter cloth. The corrected areas did not pick up ink on press.However, plates that had been rinsed with tap water showed toning in thecorrected areas, which could only be removed by a subsequent treatmentwith plate cleaner.

[0107] As the water recycling system iK works with a high-pressure pump,the additive needs to have an antifoaming agent.

[0108] Although the invention has been particularly shown and describedwith reference to the preferred embodiments, those skilled in the artwill appreciate that various modifications and changes in form anddetails may be made without departing from the spirit and scope of theinvention. Having described the invention, we now claim the followingand their equivalents.

What I claim:
 1. An additive composition comprising: (a) at least onewater-soluble film-forming polymer; and, (b) at least one compoundselected from the group consisting of phosphonic acid derivatives offormula I

in which X is C₂-C₆ alkylene, or

in which: k is 0 or 1; m is 1, 2, or 3; p is 1, 2, or 3; r is an integerfrom 10-20; R¹ and R³ are each independently H or C₁-C₄ alkyl; R² and R⁴are each independently H, OH, or C₁-C₄ alkoxy; and Y is—R⁶N—(CH2)_(n)—(NR⁵ )_(q)—, in which q is 0 or 1, n is an integer from 0to 8 and R⁵ and R⁶ are each independently H, C₁-C₄ alkyl, or—CH₂—P(O)(OH)₂.
 2. The additive composition of claim 1 furthercomprising: (c) at least one pH regulating agent capable of maintainingthe pH value of an aqueous solution at about 7 or below.
 3. The additivecomposition of claim 2 in which: (a) the water-soluble film-formingpolymer comprises about 0.1 to about 80 wt % of the additivecomposition, based on the total additive composition; (b) the compoundselected from phosphonic acid derivatives of formula I comprises about0.1 to 30 wt % of the additive composition, based on the total additivecomposition; and (c) the pH regulating agent comprises about 0.01 toabout 1 mol of the pH regulating agent per 100 g of total additivecomposition.
 4. The additive composition of claim 1 or claim 2 furthercomprising at least one additive selected from the group consisting ofantifoaming agents, biocides, corrosion inhibitors, chelating agents andsurfactants.
 5. The additive composition of claim 4 in which: (d) theantifoaming agent comprises about 0 to 5 wt % of the additivecomposition, of based on the total additive composition; (e) the biocidecomprises about 0 to 80 wt % of the additive composition, based on thetotal additive composition; (f) the corrosion inhibitor comprises about0 to 10 wt % of the additive composition, based on the total additivecomposition; (g) the chelating agent comprises about 0 to 30 wt % of theadditive composition, based on the total additive composition; and (h)the surfactant comprises about 0 to 50 wt % of the of the additivecomposition, based on the total additive composition.
 6. The additivecomposition of claim 5 in which the water-soluble film-forming polymeris selected from the group consisting of gum arabic, dextrin, wasteddextrine, enzyme-modified dextrin, etherified enzyme-modified dextrin,carboxymethylated starch, starch phosphate, octenyl succinated starch,alginates, carboxymethyl cellulose, carboxyethyl cellulose, hydroxyethylcellulose, methyl cellulose, hydroxypropyl methyl cellulose, polyvinylalcohol and derivatives thereof, polyvinyl pyrrolidone, polyacrylamideand copolymers thereof, polyacrylic acid and copolymers thereof,styrene/maleic anhydride copolymers, vinyl methyl ether/maleic anhydridecopolymers, and vinyl acetate/maleic anhydride copolymers.
 7. Theadditive composition of claim 5 in which the pH regulating agentcomprises a compound selected from the group consisting of citric acid,citric acid salts, boric acid, acetic acid, propionic acid, succinicacid, phosphates, phosphoric acid, and aminotris-(methylene-phosphonicacid).
 8. The additive composition of claim 5 in which the phosphonicacid derivative is selected from the group consisting ofhydroxyethanediphosphonic acid and salts thereof,hexamethylenediaminotetra(methylenephosphonic acid) and salts thereof,aminotris(methylenephosphonic acid) and salts thereof, and mixturesthereof.
 9. The additive composition of claim 5 in which the antifoamingagent is selected from the group consisting of silicone-basedantifoaming agents and mixtures thereof.
 10. The additive composition ofclaim 5 in which the biocide is selected from the group consisting ofN-methylol-chloroacetamide, benzoic acid, phenol and its derivatives,formalin, imidazole derivatives, sodium dehydro-acetate, isothiazolinonederivatives, benzotriazole derivatives, amidines, guanidine derivatives,quaternary ammonium salts, pyridine, quinoline derivatives, diazine,triazole derivatives, oxazoles derivatives, and oxazine derivatives, andmixtures thereof.
 11. The additive composition of claim 5 in which thecorrosion inhibitor is selected from the group consisting of magnesiumnitrate, zinc nitrate, calcium nitrate, sodium nitrate, potassiumnitrate, lithium nitrate, ammonium nitrate, and mixtures thereof. 12.The additive composition of claim 5 in which the chelating agent isselected from the group consisting of ethylenediamine-tetraacetic acid,the potassium salt thereof, and the sodium salt thereof;diethylenetriamine-pentaacetic acid, the potassium salt thereof, and thesodium salt thereof; triethylenetetramine-hexaacetic acid, the potassiumsalt thereof, and the sodium salt thereof; hydroxyethylethylenediamine-triacetic acid, the potassium salt thereof, and thesodium salt thereof; nitrilotriacetic acid, the potassium salt thereof,and the sodium salt thereof; 1,2-diaminocyclohexane-tetraacetic acid,the potassium salt thereof, and the sodium salt thereof;1,3-diamino-2-propanol tetraacetic acid, the potassium salt thereof, andthe sodium salt thereof; 2-phosphonobutanetricarboxylic acid-1,2,4, thepotassium salt thereof, and the sodium salt thereof;2-phosphonobutane-tricarboxylic acid-2,3,4, the potassium salt thereof,or the sodium salt thereof; 1-phosphonoethane-tricarboxylic acid-2,2,2,the potassium salt thereof, and the sodium salt thereof;aminotri-(methylene-phosphonic acid) the potassium salt threreof, andthe sodium salt thereof; sodium gluconate; and mixtures thereof.
 13. Theadditive composition of claim 5 in which the surfactant is selected fromthe group consisting of fatty acid salts, abietic acid salts,hydroxyalkanesulfonic acid salts, dialkyl sulfosuccinate salts, alkylnaphthalenesulfonate salts, alkyl-phenoxy polyoxyethylenepropylsulfonatesalts, polyoxyethylene alkylsulfophenyl ether salts, sodium salt ofN-methyl-N-oleyltaurine, disodium salt of N-alkylsulfosuccinic acidamide, petroleum sulfonic acid salts, sulfated castor oil, sulfatedtallow, sulfuric acid ester salts of fatty acid alkyl esters,alkylsulfate ester salts, polyoxyethylene alkyl ether sulfuric acidester salts, fatty acid monoglyceride sulfuric acid ester salts,polyoxyethylene alkylphenyl ether sulfuric acid ester salts,polyoxyethylene styrylphenyl ether sulfuric acid ester salts,alkylphosphate ester salts, polyoxyethylene alkyl ether phosphoric acidester salts, polyoxyethylene alkylphenyl ether phosphoric acid estersalts, partially saponified styrene-maleic anhydride copolymers,partially saponified olefin-maleic anhydride copolymers, condensates ofnaphthalene sulfonic acid salts and formalin, alkylbenzene sulfonates,alkane sulfonates, alkylsulfates, alkylethersulfates, glycerin, ethyleneglycol, triethylene glycol, sorbitan fatty acid esters, alkylphenolethoxylates, fatty alcohol ethoxylates, alkyl polyglucosides,N-methylglucamides, quaternary ammonium compounds with one or twohydrophobic groups, salts of long chain primary amines, and mixturesthereof.
 14. The additive composition of claim 1 in which: thewater-soluble film-forming polymer comprises about 5 to about 30 wt % ofthe additive composition, based on the total additive composition; thecompound selected from phosphonic acid derivatives of formula Icomprises about 3 to 20 wt % of the additive composition, based on thetotal additive composition; and the additive composition comprises oneor more additives selected from the group consisting of antifoamingagents, biocides, corrosion inhibitors, chelating agents andsurfactants.
 15. The additive composition of claim 2 in which: thewater-soluble film-forming polymer comprises about 5 to about 30 wt % ofthe additive composition, based on the total additive composition; thepH regulating agent comprises about 0.01 to about 0.5 mol of the pHregulating agent per 100 g of the total additive composition; the pHregulating agent is capable of keeping the pH of the aqueous compositionin the range of about pH 5 to pH 6; the compound selected fromphosphonic acid derivatives of formula I comprises about 3 to 20 wt % ofthe additive composition, based on the total additive composition; andthe additive composition comprises one or more additives selected fromthe group consisting of antifoaming agents, biocides, corrosioninhibitors, chelating agents and surfactants.
 16. An aqueous concentratecomprising: (i) an additive composition comprising: (a) at least onewater-soluble film-forming polymer; and (b) at least one compoundselected from the group consisting of phosphoric acid derivatives offormula I

in which X is C₂-C₆ alkylene or

in which: k is 0 or 1; m is 1, 2, or 3; p is 1, 2, or 3; r is an integerfrom 10-20; R¹ and R³ are each independently H or C₁-C₄ alkyl; R² and R⁴are each independently H, OH, or C₁-C₄ alkoxy; and Y is—R⁶N—(CH2)_(n)—(NR5)_(q)—, in which q is 0 or 1, n is an integer from 0to 8 and R⁵ and R⁶ are each independently H, C₁-C₄ alkyl, or—CH₂—P(O)(OH)₂; and (ii) water; in which the amount of the additivecomposition is about 40 wt % to about 90 wt %, based on the amount ofwater used in the concentrate.
 17. The aqueous concentrate of claim 16further comprising: (c) at least one pH regulating agent capable ofmaintaining the pH value of an aqueous solution below
 7. 18. The aqueousconcentrate of claim 17 in which: (a) the additive composition comprisesabout 0.1 to about 80 wt % of the water-soluble film-forming polymer,based on the total additive composition; (b) the additive compositioncomprises about 0.1 to about 30 wt % of the one or more phosphonic acidderivatives of formula I, based on the total additive composition; and,(c) the additive composition comprises about 0.01 to about 1 mol of thepH regulating agent per 100 g of the total additive composition.
 19. Theaqueous concentrate of claim 16 or claim 17 further comprising at leastone additive selected from the group consisting of antifoaming agents,biocides, corrosion inhibitors, chelating agents and surfactants. 20.The aqueous concentrate of claim 19 in which: (d) the antifoaming agentcomprises about 0 to 5 wt % of the additive composition, of based on thetotal additive composition; (e) the biocide comprises about 0 to 80 wt %of the additive composition, based on the total additive composition;(f) the corrosion inhibitor comprises about 0 to 10 wt % of the additivecomposition, based on the total additive composition; (g) the chelatingagent comprises about 0 to 30 wt % of the additive composition, based onthe total additive composition; and (h) the surfactant comprises about 0to 50 wt % of the of the additive composition, based on the totaladditive composition.
 21. The aqueous concentrate of claim 16 in which:the water-soluble film-forming polymer comprises about 5 to about 30 wt% of the additive composition, based on the total additive composition;the compound selected from phosphonic acid derivatives of formula Icomprises about 3 to 20 wt % of the additive composition, based on thetotal additive composition; and the additive composition comprises oneor more additives selected from the group consisting of antifoamingagents, biocides, corrosion inhibitors, chelating agents andsurfactants.
 22. The aqueous concentrate of claim 17 in which: thewater-soluble film-forming polymer comprises about 5 to about 30 wt % ofthe additive composition, based on the total additive composition; thepH regulating agent comprises about 0.01 to about 0.5 mol of the pHregulating agent per 100 g of the total additive composition; the pHregulating agent is capable of keeping the pH of the aqueous compositionin the range of about pH 5 to pH 6; the compound selected fromphosphonic acid derivatives of formula I comprises about 3 to 20 wt % ofthe additive composition, based on the total additive composition; andthe additive composition comprises one or more additives selected fromthe group consisting of antifoaming agents, biocides, corrosioninhibitors, chelating agents and surfactants.
 23. The aqueousconcentrate of claim 22 in which the phosphonic acid derivative isselected from the group consisting of hydroxyethanediphosphonic acid andsalts thereof, hexamethylenediaminotetra(methylenephosphonic acid) andsalts thereof, aminotris(methylenephosphonic acid) and salts thereof,and mixtures thereof.
 24. A method for processing an imagewise exposedlithographic printing plate, the method comprising, in order, the stepsof: (i) applying a developer to the exposed plate; and (ii) rinsing theplate with rinse water; in which the rinse water comprises: (a) at leastone water-soluble film-forming polymer; (b) at least one compoundselected from the group consisting of phosphoric acid derivatives offormula I

in which X is C₂-C₆ alkylene or

in which: k is 0 or 1; m is 1, 2, or 3; p is 1, 2, or 3; r is an integerfrom 10-20; R¹ and R³ are each independently H or C₁-C₄ alkyl; R² and R⁴are each independently H, OH, or C₁-C₄ alkoxy; and Y is—R⁶N—(CH2)_(n)—(NR⁵)_(q)—, in which q is 0 or 1, n is an integer from 0to 8 and R⁵ and R⁶ are each independently H, C₁-C₄ alkyl, or—CH₂—P(O)(OH)₂.
 25. The method of claim 24 in which the rinse waterfurther comprises: (c) at least one pH regulating agent capable ofmaintaining the pH value of an aqueous solution about 7 or below. 26.The method of claim 24 in which the rinse water comprises about 0.0004to 8 wt % of the water-soluble film-forming polymer, based on the amountof rinse water.
 27. The method of claim 24 in which the rinse watercomprises about 0.0004 to 3 wt % of the phosphonic acid derivative,based on the amount of rinse water.
 28. The method of claim 25 in whichthe rinse water comprises about 1 to 100 mmole of pH regulating agentper liter of rinse water.
 29. The method of claim 25 in which the rinsewater is recirculated.
 30. The method of claim 25 in which the additivecomposition additionally comprises at least one additive selected fromthe group consisting of antifoaming agents, biocides, corrosioninhibitors, chelating agents, and surfactants.
 31. The method of claim30 in which the amount of the antifoaming agent in the rinse water isabout 0 to 0.5 wt % based on the amount of rinse water.
 32. The methodof claim 30 in which the amount of the biocide in the rinse water isabout 0 to 8 wt % based on the amount of rinse water.
 33. The method ofclaim 30 in which the amount of the corrosion inhibitor in the rinsewater is about 0 to 1 wt % based on the amount of rinse water.
 34. Themethod of claim 30 in which the amount of the chelating agent in therinse water is about 0 to 3 wt % based on the amount of rinse water. 35.The method of claim 30 in which the amount of the surfactant in therinse water is about 0 to 5 wt % based on the amount of rinse water. 36.The method of claim 30 in which the rinse water is recirculated.
 37. Themethod of claim 30 in which the rinse water is prepared by adding theadditive composition to water selected from the group consisting of tapwater, well water, demineralized water, and recirculated rinse water.38. The method of claim 24 in which the rinse water is prepared byadding the additive composition to water selected from the groupconsisting of tap water, well water, demineralized water, andrecirculated rinse water.
 39. The method of claim 25 in which the rinsewater is prepared by adding the additive composition to water selectedfrom the group consisting of tap water, well water, demineralized water,and recirculated rinse water.
 40. The method of claim 24 in which: therinse water is prepared by adding an aqueous concentrate to waterselected from the group consisting of tap water, well water,demineralized water, and recirculated rinse water; and the aqueousconcentrate comprises about 40 to 90 wt % of the additive composition,based on the amount of water in the concentrate.
 41. The method of claim25 in which: the rinse water is prepared by adding an aqueousconcentrate to water selected from the group consisting of tap water,well water, demineralized water, and recirculated rinse water; and theaqueous concentrate comprises about 40 to 90 wt % of the additivecomposition, based on the amount of water in the concentrate.
 42. Themethod of claim 25 in which the lithographic printing plate comprises alight-sensitive layer comprising a novolac resin and aradiation-sensitive component that is converted to a carboxylic acid onexposure to radiation.
 43. The method of claim 42 in which: thewater-soluble film-forming polymer comprises about 5 to about 30 wt % ofthe additive composition, based on the total additive composition; thepH regulating agent comprises about 0.01 to about 0.5 mol of the pHregulating agent per 100 g of the total additive composition; the pHregulating agent is capable of keeping the pH of the aqueous compositionin the range of about pH 5 to pH 6; the compound selected fromphosphonic acid derivatives of formula I comprises about 3 to 20 wt % ofthe additive composition, based on the total additive composition; andthe additive composition comprises one or more additives selected fromthe group consisting of antifoaming agents, biocides, corrosioninhibitors, chelating agents and surfactants.
 44. The method of claim 43in which the phosphonic acid derivative is selected from the groupconsisting of hydroxyethanediphosphonic acid and salts thereof,hexamethylenediaminotetra(methylenephosphonic acid) and salts thereof,aminotris(methylenephosphonic acid) and salts thereof, and mixturesthereof.
 45. The method of claim 44 in which the method does notcomprise a gumming step.
 46. The method of claim 24 in which the methoddoes not comprise a gumming step.
 47. A lithographic printing plate, thelithographic printing plate prepared by, in order, the steps of: (i)applying a developer to an imagewise exposed lithographic printingplate; and (ii) rinsing the imagewise exposed lithographic printingplate with rinse water; in which the rinse water comprises: (a) at leastone water-soluble film-forming polymer; (b) at least one compoundselected from the group consisting of phosphoric acid derivatives offormula I

in which X is C₂-C₆ alkylene or

in which: k is 0or 1; m is 1, 2, or 3; p is 1, 2, or 3; r is an integerfrom 10-20; R¹ and R³ are each independently H or C₁-C₄ alkyl; R² and R⁴are each independently H, OH, or C₁-C₄ alkoxy; and Y is—R⁶N—(CH2)_(n)—(NR⁵)_(q)—, in which q is 0 or 1, n is an integer from 0to 8 and R⁵ and R⁶ are each independently H, C₁-C₄ alkyl, or—CH₂—P(O)(OH)₂.
 48. The lithographic printing plate of claim 47 in whichthe rinse water further comprises: (c) at least one pH regulating agentcapable of maintaining the pH value of an aqueous solution about 7 orbelow.
 49. The lithographic printing plate of claim 47 or claim 48 inwhich the rinse water additionally comprises at least one additiveselected from the group consisting of antifoaming agents, biocides,corrosion inhibitors, chelating agents, and surfactants.
 50. Thelithographic printing plate of claim 47 in which: the water-solublefilm-forming polymer comprises about 5 to about 30 wt % of the additivecomposition, based on the total additive composition; the compoundselected from phosphonic acid derivatives of formula I comprises about 3to 20 wt % of the additive composition, based on the total additivecomposition; and the additive composition comprises one or moreadditives selected from the group consisting of antifoaming agents,biocides, corrosion inhibitors, chelating agents and surfactants. 51.The lithographic printing plate of claim 48 in which: the water-solublefilm-forming polymer comprises about 5 to about 30 wt % of the additivecomposition, based on the total additive composition; the pH regulatingagent comprises about 0.01 to about 0.5 mol of the pH regulating agentper 100 g of the total additive composition; the pH regulating agent iscapable of keeping the pH of the aqueous composition in the range ofabout pH 5 to pH 6; the compound selected from phosphonic acidderivatives of formula I comprises about 3 to 20 wt % of the additivecomposition, based on the total additive composition; and the additivecomposition comprises one or more additives selected from the groupconsisting of antifoaming agents, biocides, corrosion inhibitors,chelating agents and surfactants.
 52. The lithographic printing plate ofclaim 50 in which the method does not comprise a gumming step.
 53. Thelithographic printing plate of claim 51 in which the method does notcomprise a gumming step.